Projection welded needle guide

Abstract

Projection welding is used to join a needle guide member and a valve seat member together preparatory to their assembly into the nozzle of a fuel injector. Various embodiments are disclosed, including various ways for creating the projections. In the preferred embodiment the projections on the end face of the guide member are made my forming a small holes in the frustoconical surface of the guide plate. As the tool is used to form the small holes in the guide plate, the material of the guide plate is displaced creating small projections from the frustoconial guide surface.

What is claimed is: 
     
       1. The combination of a seat member and a guide member for a fuel injector wherein on of said members has weld projections for engaging the other said members preparatory to joining of the two members together by conducting welding current through them to turn the projections into welds that join the two members, in which said one member comprises a corresponding depression immediately adjacent each weld projection, and in which said seat and guide members share a common main longitudinal axis, said one member comprises a frustoconical surface, each said corresponding depression is contained in said frustoconical surface, and each said weld projection adjoins the corresponding depression in a direction that is parallel with said main longitudinal axis. 
     
     
       2. The combination set forth in claim 1 in which said one member comprises an axially facing surface that adjoins said frustoconical surface, and each said weld projection projects from said axially facing surface in a direction that is parallel with said main longitudinal axis. 
     
     
       3. The combination set forth in claim 2 in which said one member is said guide member, said seat member comprises a frustoconical surface portion, and said weld projections are disposed to engage said frustoconical surface portion of said seat member. 
     
     
       4. The combination set forth in claim 3 in which there are three such weld projections, and corresponding depressions, arranged 120 degrees apart about said main longitudinal axis. 
     
     
       5. The combination set forth in claim 4 in which each said depression comprises a pointed hole. 
     
     
       6. The combination set forth in claim 1 in which said one member is said guide member, said seat member comprises a frustoconical surface portion, and said weld projections are disposed to engage said frustoconical surface portion of said seat member. 
     
     
       7. The combination set forth in claim 6 in which there are three such weld projections, and corresponding depressions, arranged 120 degrees apart about said main longitudinal axis. 
     
     
       8. The combination set forth in claim 1 in which there are three such weld projections, and corresponding depressions, arranged 120 degrees apart about said main longitudinal axis. 
     
     
       9. The combination of a seat member and a guide member for a fuel injector wherein one of said members has weld projections for engaging the other of said member preparatory to joining the two members together by conducting welding current through them to turn the projections into welds that join the two members, in which said one member comprises a corresponding depression immediately adjacent each weld projection, and in which each said depression comprises a pointed hole. 
     
     
       10. The combination set forth in claim 9 in which said seat and guide members share a common main longitudinal axis, said one member comprises a frustoconical surface, each said corresponding depression is contained in said frustoconical surface, and each said weld projection adjoins the corresponding depression in a direction that is parallel with said main longitudinal axis. 
     
     
       11. The combination set forth in claim 10 in which said one member comprises an axially facing surface that adjoins said frustoconical surface, and each said weld projection projects from said axially facing surface in a direction that is parallel with said main longitudinal axis. 
     
     
       12. The combination set forth in claim 11 in which there are three such weld projections, and corresponding depressions, arranged 120 degrees apart about said main longitudinal axis. 
     
     
       13. The combination set forth in claim 10 in which there are three such weld projections, and corresponding depressions, arranged 120 degrees apart about said main longitudinal axis. 
     
     
       14. The combination set forth in claim 9 in which there are three such weld projections and corresponding depressions, arranged 120 degrees apart about a main longitudinal axis that is shared by said seat and guide members. 
     
     
       15. The combination set forth in claim 14 in which said one member comprises an axially facing surface that adjoins a frustoconical surface, and each said weld projection projects from said axially facing surface in a direction that is parallel with said main longitudinal axis. 
     
     
       16. The combination of a seat member and a guide member for a fuel injector wherein one of said members has weld projections for engaging the other of said members preparatory to joining of the two members together by conducting welding current through them to turn the projections into welds that join the two members, and in which said one member comprises an axially facing surface adjoining a frustoconical surface, and each said weld projection projects from said axially facing surface in a direction away from said frustoconical surface. 
     
     
       17. The combination set forth in claim 16 in which said one member is said guide member. 
     
     
       18. The combination set forth in claim 16 in which there are three of said weld projections arranged circumferentially about said one member. 
     
     
       19. The combination set forth in claim 16 in which said one member comprises, for each weld projection, a corresponding depression that is disposed in said frustoconical surface proximate the corresponding weld projection. 
     
     
       20. The combination set forth in claim 16 in which said other member comprises a frustoconical surface portion, and said weld projections are disposed to engage said frustoconical surface portion of said other member.